Trimming device for sewing machine



Dec. 29, 1964 c. e. PICKETT TRIMMING DEVICE FOR SEWING MACHINE 3Sheets-Sheet 1 Filed Sept. 10, 1962 INVENTOR. CHARLES G. PICKETT W7:ATTORNEY Dec. 29, 1964 c. G. PICKETT TRIMMING DEVICE FOR SEWING MACHINE5 Sheets-Sheet 2 Filed Sept. 10, 1962 wwmwwmimpl WWILV 1 1 II as 87 I03INVENTOR WITNESS Fig, 5, CHARLES G. PICKETT F5 AT ORNEY Dec. 29, 1964 c.e. PICKETT 3,163,136

TRIMMING DEVICE FOR SEWING MACHINE Filed Sept. 10, 1962 5 Sheets-Sheet 3n I26 92 76 5" I02 (W47 Fig. 7.

INVENTOR. CHARLES G. PICKETT WITNESS United States Patent Ofiice fidhdid Fatented Eco. 29, 1964 3,153,136 TRUHMING DEVECE FGR SEWiING MAQHKNECharles G. Pickett, Dover, N1, assignor to The Singer Company, acorporation of New Jersey Filed Sept. It 1962, Ser. No. 222,421 Claims.(Cl. 112--13ti) This invention relates to trimming devices and moreparticularly to trimming devices designed to sever into short lengths along sewed strip of material as the said strip of material is fed awayfrom a sewing machine on which it has been sewed, and a primary objectof the present invention is to provide an improved device of thischaracter.

Another obiect of the invention is to provide an irnproved trimmingdevice having means for raising and lowering the trimming device betweentrimming operations.

A further object of the invention is to provide an improved trimmingdevice having means for stopping one portion of a moving strip andthereby causing said strip to form a loop at a position suitable fortrimming.

A still further object of the invention is to provide an improved meansfor mounting a trimming device on a sewing machine so that the positionof the trimming device can be adjusted easily.

A further object of the invention is to provide an improved means formoving the scissors of a trimming device to and from a cutting position.

Another object of the invention is to provide an improved means forstopping movement of the trimming device at the end of its cycle ofoperation.

Another object of the invention is to provide a trimming device whichcan be started at will, and which, when once started, will clamp a stripbeing fed from a sewing machine, lower a pair of scissors to a cuttingposition, move the scissors across the strip to perform the cuttingoperation, raise the presser device and the scissors to a clear positionand stop movement of the presser device and the scissors.

Having in mind the above and other objects that will be evident from anunderstanding of this disclosure, the invention comprises the devices,combinations and arrangements of parts as illustrated in the presentlypreferred embodiment of the invention which is hereinafter set forth insuch detail as to enable those skilled in the art readily to understandthe function, operation, construction and advantages of it when read inconjunction with the accompanying drawings in which:

FIG. 1 is an elevational end view of a sewing machine to which has beenattached a trimming device embodying he present invention,

P18. 2 is an elevational view of the trimming device taken substantiallyon the line 2-2 of FIG. 1,

PEG. 3 is a schematic view of the trimming device, the parts being shownin an inactive raised position,

FIG. 4 is a view similar to FIG. 3 but showing an arm of the trimmingdevice lowered to a clamping position whereby the sewed strip being fedfrom the sewing machine is clamped against the work supporting surfaceof the sewing machine bed,

FIG. 5 is a view similar to FIG. 3 wherein the solid line portions ofFIG. 5 show parts of the trimming device in the positions they assumeprior to beginning a cut and wherein the dash-dash line portions showparts in the position they assume after completion of the cut,

FIG. 6 is a view similar to FIG. 3 but showing parts of the trimmingmechanism as they begin to rise on their way to assuming the positionshown in FIG. 3, and

FIG. 7 is a diagram showing the electric circuit.

FIG. 1 shows the trimming device 16 of this invention as associated withand supported from a sewing machine 17. The sewing machine 17 has manyconventional parts,

including a work supporting plate 18, a throat plate 19 carried by theplate 18, a feed dog 21 above which is supported a head 22 having a faceplate 23 held in place by screws 24. The head 22 supports a needle bar26, a presser bar 27, and take-up lever 28, and the face plate 23 bymeans of a plurality of screws and nuts 29 supports one flange of anangle bracket 3 the other flange of which supports a stud 32. The stud32 in turn supports a second angle bracket 33 and a third angle bracket34 is held to the arm (not shown) of the sewing machine 17 by means of astud 35. The two brackets 33 and 3d support a pair of rods 36 and 37 andthe trimming device 16 is carried by the rods 36 and 37 in such a mannerthat the trimming device 16 can be adjusted to any desired positionlongitudinally of the rods. Also, because the angle brackets 33 and 34are provided with a plurality of sets of holes 3838, the trimming device16 can be adjusted toward or away from the sewing machine 17 by placingthe rods 36 and 37 in the selected holes Fifi-38.

Specifically the trimming device 16 is held to the rods 36 and 37 in thefollowing manner. The rod 36 passes through a block 41 carried on therear face of an upstanding mounting plate 42 and the rod 37 passesthrough a block 43 which is held to a thin plate 44 and the thin plate44- is secured to the mounting plate 42. A gear box 46 of an electricmotor 47 is secured to the thin plate 44 and the electric motor 47drives gears (not shown) in the gear box 46 which gears in turn drive,at a low speed, a shaft 48 which carries a pinion 49.

The mounting plate 42, as best seen in FIGS. 5 and 6, is substantiallyI-shaped in form and thereby has two upper arms 51 and 52 and two lowerarms 53 and 54 extending horizontally outwardly from the main body ofthe plate 42.. The lower arm 53 carries (FIG. 4) a rotatable shaft seand the lower arm 54 carries (FIG. 6) a rotatable shaft 57. The ends ofthe shafts 56 and 57 to the rear of the mounting plate 42 respectivelycarry (FIG. 2) gears 53 and 59 both of which are in mesh with and aredriven by the pinion 4%. The ends of the shafts 56 and 57 in front ofthe mounting plate 42 respectively carry ends of a pair of crank arms atand 62. The distal ends of the arms 61 and 62 respectively carryforwardly projecting pivot pins 63 and 64 and on the front ends of thesepins 63 and 64 is pivotally carried a movable plate 66. The upper end ofthe mounting plate 42 is connected to the upper end of the movable plate66 by a third crank arm 67, the arm 67 being connected to the plate 42by a pivot pin 68 and the arm 67 being connected to the plate 66 by apivot pin 69.

From the above it can be seen that, as the motor 47 drives gears in thegear box 46 to slowly drive the shaft 43 and the pinion 49, the pinion49 drives the two gears 58 and 59 to rotate the shafts 56 and 57 to turnthe crank arms 61 and 62. Then the crank arms 61 and 62 through theirpins 63 and 64 drive the movable plate 66 from the upper position shownin FIG. 3 to the right side position shown in FIG. 4, to the loweredright side position shown in solid lines in FIG. 5, to the lowered leftside position shown by dash-dash lines in FIG. 5, to the [left raisedposition shown in FIG. 6 and finally back to the fully raised positionshown in FIG. 3. As a matter of interest, it should be pointed out thatthe position of the movable plate 66 shown in FIG. 3 is partway betweenthe two positions shown in FIG. 5.

Arms 51 and 53 (FIG. 4) are formed with aligned cylindrical holes 71 and73 and arms 52 and 54 are formed with aligned cylindrical holes 72 and74. A cylindrical shank 76 of a work-engaging or presser device 77 isslidably carried in the holes 71-73, and a cylindrical guide rod 78 isslidably carried in the holes 72-74. Theupper ends of the shank 76 andthe upper end of the guide rod 7% are connected by a horizontallydisposed bar 7%. Screws 818l carried by opposite ends of the bar 79 areconnected by tensioin springs 82-$2 to pins 83-83 carried by the lowerarms 53 and 54 of the mounting plate 42. The springs 8282 provide adownward bias for the rod 78 and especially for the presser device 77.The lower end of the presser device 77 has a horizontal bar 84, a bentbar 86 (FIG. 1) and a sole portion 87, the sole portion 87 when in itslowered position, as shown in FIGS. 1 and 2, presses on the uppersurface of a strip of sewed material as the said strip of material 88 isfed away from the sewing machine 17 in a known manner by the feed dog21. From FIGS. 1 and 2 it can be seen that when the sole portion 87rests on the material 88 it stops a portion of the material 88 and thusthe material 88 is forced to form a loop 8%, because the feed dog 21continues to feed one portion of the material while the sole portion 87holds another portion of the material 88.

Reference to FIG. 2 shows that the crank arm 67 differs from crank arms61 and 62 in that the crank arm 67 has an edge cam 91 which, as bestseen in FIG. 6, functions to raise the bar 79 against the bias of thesprings 8282. Because of the cam 91 and the bar 79, the sole portion 87is (FIG. 3) raised free from contact with the strip of material 88 or isallowed to contact (FIGS. 4 and the material 88. The shank '76 carries alug 92 which when the movable plate 66 is in the raised position (FIG.3) engages and opens the electrical contacts of a normally closedelectric limit switch )4 carried by the upper arm 51 of the mountingplate 42. The function of the switch 94 will be described in more detailhereinafter.

The lower end of the movable plate 66 carries a front protuberance 96which is provided with a pair of downwardly extending bores 9797designed to accommodate a pair of upstanding rods 98 and 98. A plate MP1is mounted on the reverse side of the lower ends of the rods 9898 and ahigh speed electric motor 162 is mounted on the rear side of the plate1-91, and the lower end of the plate 161 is formed into a lower scissoror cutting blade 103. Cooperating with lower scissor blade 193 is anupper scissor or cutting blade 164 which is pivotally mounted on a pin106 carried by the blade 163. The upper blade 3 is pivotally connectedto the lower end of a link 107 and the upper end of the link 1t)? isdriven, through a hole 1% formed in the plate 101, by an eccentric 109carried by the end of the shaft of the motor 132. The upper end of oneof the rods 98 carries diametrical pin 111 which engages the upperportion of the protuberance 96 when the parts are in the position shownin FIG. 3, thus holding the blades 103 and 164 above the work supportingplate 13. A bracket 112 (FIGS. 1 and 2), one end of which is held byrivets 113113 to the rods 9898, supports a shield 114 which prevents theoperators hand from engaging the blades 103 and MP4.

The electrical equipment used to drive and control the two motors 47 and1M of the trimming device 16 preferably comprises (1) a transformer 116for providing a low voltage source of A.C. electric power, (2) thepreviously mentioned normally closed limit switch 94 for stopping thetrimming device 16 at the end of its cycle as shown in FIG. 3, (3) afoot or knee operated normally open switch 117 for starting the trimmingoperation, and (4) a full wave rectifier 118 for supplying A.C. power tothe motor 102. From FIG. 7 it can be seen that a conductor 121 extendsfrom one terminal of the low voltage secondary winding of thetransformer 116 to terminals of the parallel connected switches 94 and117, and a conductor 122 extends from the other terminals of theswitches 94 and 117 to one of the A.C. terminals of the rectifier 118and also to one terminal of the motor 47. A conductor 123 extends fromthe other terminal of the low voltage secondary winding of thetransformer 116 to the second A.C. terminal of the rectifier 118 andalso to the second terminal of the motor 47. The two D.C.

terminals of the rectifier 318 are connected by conductors 126 and 127to the terminals of the motor 18 2. From the above, it can be seen thatwhenever proper electric power is supplied to the primary of thetransformer 116 and the contacts of either switch 94 or switch 117 areclosed the motors 47 and N2 will operate. If it is assumed that parts ofthe trimming device 16 are in the positions shown in FIG. 3, the switch94 will be held open by the lug 2 and the motors 47 and 162 will bestopped. It the operator closes the switch 117 the motors 47 and 192will start to operate. Operation of the motor 47 lowers the shank 76 andthe lug $2 which causes the switch 94 to close thus causing operation ofthe motors 47 and 1&2 and these motors will continue to operate untilboth switches 94 and 117 are opened.

\Vhile operation of the trimming device 16 will be understood from theforegoing, a more complete description of the operation of the presentequipment is given below. With the parts in the position shown in FIG.3, the operator closes the switch 117. This causes the motors 47 and162. to operate. Operation of motor 102 turns the eccentric N 3 torapidly vibrate the upper blade 16% with respect to the lower blade 163to produce a cutting or scissors action. Operation of the motor 47drives gears in the box as which in turn slowly turn the shaft 4?, andthe pinion The pinion drives the gears 53 and 59 to turn the shafts 5'6and 57 thereby swinging the cranl: arms 61 and 62 to cause the movableplate 66 to execute a definite translation, which translation isprogressively shown in FIGS. 3 through 6. Movement or" the plate 66causes the cam edge crank arm 67 to operate in unison with the arms 61and 62. As the plate 66 is lowered from the position shown in FIG. 3 tothat shown in FIG. 4, the can] edge arm or allows the bar 79, which isbiased by the springs 82-82, to be lowcred. This lowers the shank 76 andthe lug 2 which disengages itself from the switch 94 which closes itscontacts. This causes the motors 47 and 192 to continue to run andpermits the operator to allow the switch 117 to open. Lowering the shank76 causes the sole portion 37 to press upon the strip of sewed material83 at a location behind the lower scissor blade 1&3. As the sewingmachine continues to operate the strip 88 continues to be fed. Thiscauses a loop 89 (FIG. 1) to form between the sole portion 87 and theshield 114. As the plate 66 is further lowered from the posit-ion shownin FIG. 4 to the solid line position shown in FIG. 5, the lower scissorblade 1%33 engages the work supporting plate 18 placing the blades 1&3and 104 in position to begin to cut the loop As the plate 66 moves fromthe solid line position shown in FIG. 5 to the position shown bydash-dash lines in the same FIG. 5, cutting of the loop 89 isaccomplished, it being remembered that the scissor blade 1% iscontinually operated by the motor 162. As the plate 66 moves from thedash-dash position shown in FIG. 5 to the position shown in FIG. 6, thecam 91 engages the bar 79 and raises the shank 76 and the sole portion57. As the plate 66 moves from the position shown in FIG. 6 to theposition shown in FIG. 3, the pin 111 engages the protuberance 96 toraise the rods 9895, and thus to raise the motor 1&2, the blades 133 and1M and the shield 11%. Also, as the plate 66 raises the shank 76, thelug 92 o ens the switch 94 to stop movement of the plate 66 by stoppingthe motor 47.

Having thus set forth the nature of the invention, what 1 claim hereinis:

1. In combination with a sewing machine having a frame including a worksupport, stitch-forming instrumentalities and work feeding mechanism foradvancing work past said stitch-forming instrumentalities: a worktrimming device mounted on said sewing machine frame and adapted tosever work at a location rearwardly of said stitch-torminginstrumentalities when viewed in the normal direction of the feed of thework, Said Work trimming device including scissors means supported forWork cutting movement and for bodiiy movement relatively to said work,actuating means for imparting both work cutting movement and bodilymovement to said wot i trimming device, a movable work engaging mem eroperable to contact and thereby interrupt the advance of a portion ofthe work being moved by the work feeding mechanism to form a looptherein so as to position the work for severance by the scissors means,and means to move said work engaging member in proper time relation withrespect to the movements of said work trimming device.

2. A work trimming device adapted for use with a sewing machine having aframe including a work support, stitch forming instrumentalities, andwork feeding mechanism for advancing work past said stitch forminginstrumentalit'ies, said trimming device comprising a mounting plate,means for supporting said mounting plate on said sewing machine, anelectric motor carried by said mounting plate, a movable plate adaptedfor being movably mounted with respect to said mounting plate, aplurality of crank arms connecting said movable plate to said mountingplate, means for driving said crank arms from said electric motor andthereby moving said movable plate with respect to said mounting plate,means slidabiy mount ed on said movable plate, a pair of scissor bladesadapted to sever the work, said scissor blades being carried by saidlast named means, an electric motor also carried by said last namedmeans and adapted for driving at least one of said scissor blades, apresser device slidably mounted on said mounting plate, biasing means,one end of which is connected to said mounting plate and the other endof which is connected for biasing said presser device downwardly to apredetermined position to contact the work and thereby to interrupt theadvance of a portion thereof, and means for raising said presser deviceagainst the bias of said biasing means to thereby disengage the presserdevice from the work and to permit its advance.

3. A work trimming device adapted for use with a sewing machine having aframe including a work support, stitch forming instrumentalities, andwork feeding mechanism for advancing work past said stitch forminginstrumentalities, said trimming device comprising a mounting plate,means for supporting said mounting plate on said sewing machine, anelectric motor carried by said mounting plate, a pinion driven by saidmotor, a pair of gears driven by said pinion, a movable plate adaptedfor being movably mounted with respect to said mounting plate, aplurality of crank arms driven by said gears and connecting said movableplate to said mounting plate and thereby moving said movable plate withrespect to said mounting plate, means slidably mounted on said movableplate, a pair of scissor blades adapted to sever the work, said scissorblades being carried by said last named means, an electric motor alsocarried by said last named means and adapted for driving at least one ofsaid scissor blades, a presser device slidably mounted on said mountingplate, biasing means, one end of which is connected to said mountingplate and the other end of which is connected for biasing said presserdevice downwardly to a predetermined position to contact the work andthereby to interrupt the advance of a portion thereof, and means forraising said presser device against the bias of said biasing means tothereby disengage the presser device from the work and to permit advancethereof.

4. A work trimming device adapted for use with a sewing machine having aframe including a work support,

stitch forming instrumentalities, and work feeding mechanism foradvancing work past said stitch forming instinmentalities, said trimmingdevice comprising a mounting plate, means for supporting said mountingplate on said sewing machine, an electric motor carried by said mountingplate, a movable plate adapted for being movably mounted with respect tosaid mounting plate, a plurality of crank arms connecting said movableplate to said mounting plate, means for driving said crank arms fromsaid electric motor and thereby moving said movable plate with respectto said mounting plate, means slidably mounted on said movable plate, apair of scissor blades adapted to sever the work, said scissor bladesbeing carried by said last named means, an electric motor also carriedby said last named mean and adapted for driving at least one of saidscissor blades, 21 presser device slidably mounted on said mountingplate, biasing means, one end of which is connected to said mountingplate and the other end of which is connected for biasing said presserdevice downwardly to a predetermined position to contact the work andthereby to interrupt the advance of a portion thereof, a bar membercarried by said presser device, a cam formed on one of said crank arms,and means for driving said cam, said cam moving said presser deviceagainst said biasing mean to thereby disengage the presser device fromthe work and to permit advance thereof.

5. A work trimming device adapted for use with a sewing machine having aframe including a work support, stitch forming instrumentalities, andwork feeding mechanism for advancing work past said stitch forminginstrumentalities, said trimming device comprising a mounting plate,means for supporting said mounting plate on said sewing machine, anelectric motor carried by said mounting plate, a pinion driven by saidmotor, a pair of gears driven by said pinion, a crank arm driven by eachof said gears, a movable plate adapted for being movably mounted withrespect to said mounting plate and carried by the free ends of saidcrank arms and thereby moving said movable plate with respect to saidmounting plate, an edge cam crank arm pivotally connected at one of itsends to said mounting plate, means pivo tally connecting the other endof said edge cam crank arm to said movable plate, a pair of rodslongitudinally slidably mounted on said movable plate, a pair of scissorblades adapted to sever the work, said scissor blades being carried bysaid pair of rods, an electric motor also carried by said pair of rodsand adapted for driving at least one of said scissor blades, a presserdevice longitudinally slidably mounted on said mounting plate, biasingmeans, one end of which is connected to said mounting plate and otherend of which is connected for biasing said presser device downwardly toa predetermined position to contact the work and thereby to interruptthe advance of a portion thereof, and a bar member carried by saidpresser device and engageable with said edge cam crank arm, said edgecam moving said presser device against said biasing means to therebydisengage the presser device from the work and to permit advancethereof.

References Cited in the file of this patent UNITED STATES PATENTS735,572 Oesterreich Aug. 4, 1903 1,154,337 Pierce Sept. 21, 19151,264,886 Bergwardt May 7, 1918 1,592,498 Mistretta July 13, 1926

1. IN COMBINATION WITH A SEWING MACHINE HAVING A FRAME INCLUDING A WORKSUPPORT, STITCH-FORMING INSTRUMENTALITIES AND WORK FEEDING MECHANISM FORADVANCING WORK PAST SAID STITCH-FORMING INSTRUMENTALITIES: A WORKTRIMMING DEVICE MOUNTED ON SAID SEWING MACHINE FRAME AND ADAPTED TOSEVER WORK AT A LOCATION REARWARDLY OF SAID STITCH-FORMINGINSTRUMENTALITIES WHEN VIEWED IN THE NORMAL DIRECTION OF THE FEED OF THEWORK, SAID WORK TRIMMING DEVICE INCLUDING SCISSORS MEANS SUPPORTED FORWORK CUTTING MOVEMENT AND FOR BODILY MOVEMENT RELATIVELY TO SAID WORK,ACTUATING MEANS FOR IMPARTING BOTH WORK CUTTING MOVEMENT AND BODILYMOVEMENT TO SAID WORK TRIMMING DEVICE, A MOVABLE WORK ENGAGING MEMBEROPERABLE TO CONTACT AND THEREBY INTERRUPT THE ADVANCE OF A PORTION OFTHE WORK BEING MOVED BY THE WORK FEEDING MECHANISM TO FORM A LOOPTHEREIN SO AS TO POSITION THE WORK FOR SEVERANCE BY THE SCISSORS MEANS,AND MEANS TO